Using Bing Map in web application

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VB

ASP.NET

Javascript

I am using bing map in my webapplication and i have javascript functions to display map, add push pin
Below are the functions

var map = new Microsoft.Maps.Map(document.getElementById("mapDiv"), { credentials: "AlkUIczX_RUWzPNUFvZKvPibJQ6JRazm0A8GLA30WPMllJETWxw6ElDXZSe5ao84" });
//add pin to log,lat specified
function setMapLocation(lat,longit) {
    //    var location = new Microsoft.Maps.Location(48.03, -122.4);
    var location = new Microsoft.Maps.Location(lat, longit);
    var pushpin = new Microsoft.Maps.Pushpin(location);
    map.entities.push(pushpin);
    map.setView({ center: location, zoom: 10 });
}
// Add pushpin to location and get lat and long
function GetMap() {
    //Retrieve the location of the map center
    var center = map.getCenter();
    //Add a pin to yhe center of the map
    var pin = new Microsoft.Maps.Pushpin(center, { draggable: true });
    //    Add a handler top the pushpin drag
    Microsoft.Maps.Events.addHandler(pin, 'mouseup', DisplayLoc);
    map.entities.push(pin);
}
//Get lat and long. of the pushpin
function DisplayLoc(e) {
    if (e.targetType == 'pushpin')
     {
     var pinLoc = e.target.getLocation();
    return  pinLoc.latitude + ", " + pinLoc.longitude;
      }
}

I need to
1) pass latitude and longitude as parameter from my vb.net code to "setMapLocation" javascript function
2) get return value of "DisplayLoc" javascript function which is latitude and longitude to vb.net code.
Can anyone help me how to do this please....